OpenProtect is an anti-spam server that filters spam and blocks viruses, phishing, and other malware. Acts as an SMTP gateway and integrates with any email server like Postfix, Sendmail, qmail, Exim, Microsoft Exchange, Lotus Domino, Zimbra, etc.

Oculus Server Monitor uses a plain text, human readable protocol to export server information to any client that connects to it. It supports a plugin system for commands, an XML-style configuration file, and IP-based access control. Odie, the Oculus Daemon InterfeacE, is a rich Web application that polls a list of hosts for their status.

Zentyal Server aims at offering small and medium businesses (SMBs) a native drop-in replacement for Windows Small Business Server and Microsoft Exchange Server which can be set up in less than 30 minutes and is both easy to use and affordable.

EZblue Business Server is a complete software
package consisting of the EZblue Linux OS, a
Debian-based Linux. The Business Server
applications and the EZblue Magellan desktop
client software are all loaded on one CD. It is
fast and simple to install. It provides a fully
integrated file server, print server, Web server,
and mail server. You can use it for your home or
business.

check_mssql_health is a plugin for Nagios that allows you to monitor an MS SQL Server. Among the list of metrics are time to login, buffer cache hit rate, page life expectancy, full table scan rate, free space in databases, batch requests/second, and many more. Installation of the DBD::Sybase Perl module is required.

ScopePort is a remote monitoring system that aims to provide a very easy and time saving configuration interface. It lets you monitor your servers with graphs without spending a lot of time for configuration.